DC Microplasma Jet for Local a:C-H Deposition Operated in SEM Chamber

Area of Science:

• Materials Science
• Plasma Physics
• Surface Engineering

Background:

• Precise control over thin film deposition is crucial for microfabrication.
• In-situ characterization techniques like SEM offer high-resolution imaging of deposition processes.
• Plasma-based deposition methods provide versatile routes for material synthesis.

Purpose of the Study:

• To propose and demonstrate a DC micro plasma jet system for localized micro-deposition of a:C-H films.
• To investigate the feasibility of depositing a:C-H films within the ambient vacuum of a scanning electron microscope (SEM) chamber.
• To analyze the characteristics of the deposited films.

Main Methods:

• A DC micro plasma jet was designed using an orifice shaped gas nozzle (OGN) for localized acetylene (C₂H₂) gas delivery.
• The system was integrated into a SEM chamber with a silicon (Si) wafer as the cathode at a 200 μm gap distance.
• Positive DC voltage was applied to the OGN, generating C₂H₂ plasma, and deposition was monitored via SEM and characterized by surface profiler and Raman spectroscopy.

Main Results:

• A symmetric, mountain-shaped a:C-H film of 5 μm height was successfully deposited in 15 seconds.
• The deposition process showed self-termination due to the insulating nature of the deposited film, leading to increased voltage and decreased current.
• Film deposition was optimized by varying gas flow rate, gap distance, voltage, current, and deposition time.

Conclusions:

• The developed DC micro plasma jet is effective for localized micro-deposition of a:C-H films within a SEM.
• The self-terminating nature of the deposition offers a degree of process control.
• This technique holds potential for in-situ microfabrication and material analysis.